An issue was discovered in MBed OS 6.16.0. Its hci parsing software dynamically determines the length of certain hci packets by reading a byte from its header. Certain events cause a callback, the logic for which allocates a buffer (the length of which is determined by looking up the event type in a table). The subsequent write operation, however, copies the amount of data specified in the packet header, which may lead to a buffer overflow. This bug is trivial to exploit for a denial of service but is not certain to suffice to bring the system down and can generally not be exploited further because the exploitable buffer is dynamically allocated.
The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow.
| Link | Tags |
|---|---|
| https://github.com/mbed-ce/mbed-os/blob/54e8693ef4ff7e025018094f290a1d5cf380941f/connectivity/FEATURE_BLE/libraries/cordio_stack/ble-host/sources/hci/dual_chip/hci_evt.c#L3018 | product |
| https://github.com/mbed-ce/mbed-os/pull/385 | patch vendor advisory issue tracking |